"Benefits of Blueberries for Blood Pressure May Be Blocked by Yogurt"
A trio of Harvard studies that followed more than 100,000 women
for more than a decade found that those consuming
the most anthocyanins (the brightly colored pigments found
in berries, like blueberries and strawberries)
had an 8% reduction in risk of developing high blood pressure,
And the group consuming the most every day were only eating
about six strawberries worth or even just 11 blueberries, a tenth of a cup.
But maybe the biggest berry eaters just happened to have
other healthy habits and that's the real reason they did better.
After all, you're probably more likely to sprinkle blueberries on oatmeal
than bacon and eggs.
But they controlled for whole grain intake and fiber and salt
and smoking and exercise and a bunch of other things,
and the berry benefit still remained.
But you don't know for sure until you put it to the test.
A randomized, double-blind, placebo-controlled clinical trial, and—
the title gives away the thrilling conclusion:
"Daily Blueberry Consumption Improves Blood Pressure"
How can you do a double-blind trial, though, with a food?
How can you convincingly create a fake placebo blueberry?
They used whole blueberries— about a cup's worth—
but powdered them versus a lookalike placebo powder,
which had the same amount of sugar and calories as the real blueberries,
but without actual blueberries.
Those in the placebo control group: no real change over the 8-week study.
They started out 138 over 79, and ended up 139 over 80,
whereas the real blueberry group fell from 138 over 80
to 131 over 75, a significant drop.
Now, 131 is still too high.
You'd like to see at least down to 120 or even 110,
so blueberries alone may not cure you.
However, the fact that you could get a clinically significant improvement
in a killer disease by just adding
a single thing to your diet, that's pretty impressive.
Is more better?
What about twice the dose, more like 2 cups of fresh blueberries a day?
Same kind of significant drop,
but didn't seem to work any better, so one cup may do it.
Even less may work. It's never been tested.
Overall, there's been five interventional studies to date
on the effects of blueberry supplementation on blood pressure.
Put all the studies together
and the results do not show any clinical efficacy.
Wait, wait, what?
I just showed you two studies where there was this gorgeous effect.
Have I been cherry picking studies, or rather berry picking studies?
Well, if you look closely at the studies, the blueberries in the two studies
I showed you that detected a significant effect were prepared with water;
they just mixed the blueberry powder with water.
However, the blueberries in the non-significant effect studies
were prepared with yogurt or skim milk-based smoothies.
If you remember my blast-from-the-past video from like 8 years ago,
the absorption of berry nutrients can be blocked by dairy.
Mix strawberries with water
and you get a nice peak in strawberry phytonutrients
in your bloodstream within hours of consumption.
But if you instead go for strawberries with cream—
mixing the same amount of strawberries with milk instead—
significantly less makes it into your system.
The inhibitory effects of milk are thought to be due to the interaction
between the berry pigments and milk proteins.
Yeah, but does the same thing happen with blueberries?
Let's find out.
Hard to maintain the suspense when the title just gives it away.
But indeed, the antioxidant activity of blueberries is impaired by milk.
Volunteers ate a cup and a half of blueberries with water or with milk,
and the milk blocked the absorption of some phytonutrients, but not others.
So, did it really matter that much though?
Here's the spikes in the bloodstream after blueberries with water,
and here's how much is absorbed with milk.
OK, so less, but check out what happened
to the total antioxidant capacity of your bloodstream.
Eat blueberries alone, with water,
and the antioxidant power of your bloodstream
shoots up within an hour and remains elevated 5 hours later.
OK, so with milk, you'd be thinking there'd maybe less of a bump, right?
You can say that again; not just less, but less than when you started from.
You just ate a whole bowl of blueberries and ended up with less
antioxidant capacity in your body because you ate them with milk.
No wonder mixing blueberries with yogurt or milk
may abolish the blood-pressure lowering benefits.
Interestingly, full-fat milk may inhibit nutrient absorption the most,
similar to what one finds adding milk to tea: twice the reduction in in-vitro
antioxidant values with whole milk, compared to skim milk,
which is weird because we always thought
it was the milk protein that was the culprit.
This suggests there may be some
nutrient-blocking involvement from the dairy fat as well.